The invention concerns the manufacture of cable elements utilizing optical fibres for the transmission of signals.
What is hereinafter called a cable element has already been described for instance in the French Patent Application No. 2,358,666 filed on Dec. 30, 1975 and the U.S. patent application Ser. No. 877,872, filed on Feb. 15, 1978, for "Cable incorporating optical fibres" by one of the co-inventors. The cable structure comprises an armour of high mechanical strength on which a plastic material core is extruded whose cross-section shows helical grooves serving to house optical fibres laid lengthwise. Subsequent envelopes or sheathings surround a such element of a strand of such elements to form a cable in known manner. Such a cable element will hereinafter be referred to as an "element".